Polonium hydride

For almost half a century scientists had to be satisfied to work only with polonium compounds (usually in rather small amounts). The pure metal was prepared only in 1946. High-density layers of metallic polonium prepared by vacuum sublimation have a silvery colour. Polonium is a pliable low-melting metal (melting point 254°C, boiling point 962°C), its density is about 9.3 g/cm . When polonium is heated in the air it readily forms a stable oxide its basic and acidic properties are weakly manifested. Polonium hydride is unstable. Polonium forms organometallic compounds and alloys with many metals (Pb, Hg, Ca, Zn, Na, Pt, Ag, Ni, Be). When we compare Mendeleev s predictions with these properties we see how close they are to the truth. 

During the detection of ionization over the range of a-rays from polonium in a hydrogen atmosphere, abnormally rapid increases were observed when no solid window was present between the Po and the ionization chamber. This was not explainable by the volatility of Po nor to the transfer of Po together with the recoil atoms of Ra G. This was explained by the assumption that a hydride, H2P0 is formed, which diffuses into the ionization chamber. Such a compound is rapidly destroyed by a small concentration of air or through the action of a-rays. The formation of such a hydride would explain the very high absorption power of Pt and Pd for Po. 

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